how to apply hamming window to sinal

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son
son on 1 Apr 2014
Answered: dpb on 1 Apr 2014
hello, i am new in matlab. i have created the modulated signal but don't know how to apply the hamming window to the signal.
clc
clear all
close all
%%Details
Ac = 5; % carrier amplitude
fc = 10000; % carrier frequency
Am = 1; % modulating signal amplitude
fm = 1000; % modulating signal frequency
Tc = 1 / fc; % carrier period
Ts = Tc / 100; % sample interval
Pm = 1 / fm; % signal period
t = 0 : Ts : 5*Pm; % 5 cycles
Vm = Am*cos(2*pi*fm*t); % message signal
Vc = Ac*sin(2*pi*fc*t); % carrier signal
Vam = (Ac+Vm).*sin(2*pi*fc*t); % amplitude modulated signal
%%Plot three signals
figure(1)
subplot(311)
plot(t,Vm);
title('Message signal');
xlabel('Time(s)');
ylabel('Amplitude(V)');
grid
subplot(312)
plot(t,Vc);
title('Carrier singal');
xlabel('Time(s)');
ylabel('Amplitude(V)');
grid
subplot(313)
plot(t,Vam);
title('Amplitude Modulated Signal');
xlabel('Time(s)');
ylabel('Amplitude(V)');
grid
%%Plot spectrum of AM signal
L=10^24; % number of samples
k=0:L-1;
f=k./(L*Ts); % frequency in Hz
Xam=(2/L)*abs(fft(Vam,L));
figure(2)
plot(f, Xam)
title('Spectrum of modulated signal')
xlabel('Frequency(Hz)')
ylabel('Magnitude')
grid on
%%window function

Answers (1)

dpb
dpb on 1 Apr 2014
...
Vam = (Ac+Vm).*sin(2*pi*fc*t); % amplitude modulated signal
VamWindowed=Vam.*hamming(length(t),'periodic');
doc hamming
for (a little) more detail

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